Menu
An example:
a = c(10,20,30)
b = c(1,2,3)
c = c(4,5,6)
d = c(7,8,9)
df=data.frame(a,b,c,d)
library(dplyr)
df_1 = df %>% mutate(a1=sum(a+1))
How do I add "a1" after "a" (or any other defined position) and NOT at the end?
Thank you.
937
mutate() creates new columns that are functions of existing variables. It can also modify (if the name is the same as an existing column) and delete columns (by setting their value to NULL ).
mutate() adds new variables and preserves existing ones; transmute() adds new variables and drops existing ones. New variables overwrite existing variables of the same name. Variables can be removed by setting their value to NULL .
1 Adding new columns. You can add new columns to a dataframe using the $ and assignment <- operators. To do this, just use the df$name notation and assign a new vector of data to it. As you can see, survey has a new column with the name sex with the values we specified earlier.
An update that might be useful for others who find this question - this can now be achieved directly within mutate (I'm using dplyr v1.0.2).
Just specify which existing column the new column should be positioned after or before, e.g.:
df_after <- df %>%
mutate(a1=sum(a+1), .after = a)
df_before <- df %>%
mutate(a1=sum(a+1), .before = b)
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
